2.2 Entropy

Question 1

Second law of thermodynamics is?

Answer 1

Entropy will always increase in a spontaneous process

Question 2

Third law of thermodynamics is?

Answer 2

Entropy is temperature dependent

Question 3

What is absolute zero temperature?

Answer 3

Theoretical point where there is no thermal motion (reactions stop)
0 kelvin = - 273.15°C

Question 4

What is Entropy

Answer 4

The measure of disorder in the universe ~ sheldrake

Question 5

What is the symbol for entropy?

Answer 5

S

Question 6

What is entropy unit

Answer 6

J per mol per K

(NOT KJ LIKE IN ENTHALPY)

Question 7

Entropy change of system=?

Answer 7

ΔS = S products - S reactants

Question 8

Entropy change of surroundings=?

Answer 8

ΔS = Δq/T

q = heat change of surroundings
T = temperature

Question 9

Total entropy change of universe=?

Answer 9

ΔS total = ΔS system + ΔS surroundings

Question 10

For a reaction to occur spontaneously…

Answer 10

ΔS total, must be positive

Question 11

As molecular movement / motion increases, entropy…

Answer 11

Increases

Question 12

5 Entropy increase examples

Answer 12

1. Temperature increasing
2. Liquid boiling / increased moles of gas
3. Ionic solids dissolving
4. Number of molecules increasing

Question 13

Δq =

Answer 13

ΔH recation = enthalpy change of the reaction

Products enthalpy - reactants enthalpy

NOTE: SWAP SIGN FOR SURROUNDINGS

Question 14

Gibbs free energy?

Answer 14

Energy from a reaction free to do work

(allows to work if reaction is spontaneous or not)

Question 15

Gibbs Equation

Answer 15

ΔG = ΔH - TΔS

Question 16

When ΔG is less than 0

Answer 16

Exergonic

Reaction WILL be spontaneous

Question 17

When ΔG is more than 0

Answer 17

Endergonic

Reactions needs energy input to be spontaneous

Question 18

When ΔG = 0

Answer 18

System is in equilibrium

Question 19

ΔG has to always be …………… to be spontaneous

Answer 19

Negative

Question 20

Learn combinations of ΔH and ΔS when reaction is spontaneous

Answer 20

See table

Question 21

Anabolic reactions (eg amino acids 》》peptides) have a …………. ΔG

Answer 21

Positive ( ∴ NOT spontaneous)

For all simple subunits forming complex molecules

Question 22

Anabolic reactions use ……….. to allow reactions to be spontaneous

Answer 22

Coupling reactions

Pair with reactions such as hydrolysis of ATP to have an overall - ΔG